# Measurement of Mass

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• Range of Masses

## Measurement of Mass

Mass is a basic property of matter. It does not depend on the temperature, pressure or location of the object in space. The SI unit of mass is kilogram (kg).

While dealing with atoms and molecules, the kilogram is an inconvenient unit. In this case, there is an important standard unit of mass, called the unified atomic mass unit (u), which has been established for expressing the mass of atoms as 1 unified atomic mass unit
i.e. 1u = (1/12) of the mass of an atom of carbon-12 $\ce{^12_6C}$ isotope including the mass of electrons
= 1.66 × 10–27 kg

Apart from using balances for normal weights, mass of planets is measured using gravitational methods and mass of atomic particles are measured using mass spectrograph (radius of trajectory is proportional to mass of charged particle moving in uniform electric and magnetic field).

Range of Masses
The masses of the objects, we come across in the universe, vary over a very wide range. These may vary from tiny mass of the order of 10-30 kg of an electron to the huge mass of about 1055 kg of the known universe. Table below gives the range and order of the typical masses of various objects.

 Object Mass (kg) Electron 10-30 Proton 10-27 Uranium atom 10-25 Red blood cell 10-13 Dust particle 10-9 Rain drop 10-6 Mosquito 10-5 Grape 10-3 Human 102 Automobile 103 Boeing 747 aircraft 108 Moon 1023 Earth 1025 Sun 1030 Milky way galaxy 1041 Observable Universe 1055
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